A visual feature associated with reward can capture spatial attention when it is neither physically salient nor task relevant. Under naturalistic contexts, however, multiple sources of priority may jointly modulate the feature representation of stimuli. Much less is known about how these priorities interact to determine attentional selection. Here, we investigated the bottom-up mechanisms by which reward association interacts with physical salience (i.e., independent vs. interactive), and how top-down goals affect such interactions in a task requiring feature-based attention. We first trained subjects to associate dots moving in two coherent directions (i.e., up-left or up-right) with high and low reward, respectively. During test, we presented superimposed but perceptually separable dot stimuli that consisted of coherently moving dots and randomly moving dots. We manipulated the physical salience (low vs. high contrast) and reward-based salience (low vs. high reward) of the coherent motion in a factorial design. Subjects detected threshold-level speed-up events on either the coherent or random moving dots. We found that when the coherent motion was favored by top-down goal, high reward-associated direction received higher priority than low reward-associated direction independent of its physical salience. However, when the random motion was favored by top-down goal, high reward-associated direction was more prioritized than low reward-associated direction only when it was also physically salient. These findings suggest that reward differentially interacts with physical salience, depending on the allocation of top-down attention. Top-down attention towards the reward-associated feature allowed the priority to be independently driven by the two bottom-up sources of salience, whereas top-down attention away from the reward-associated feature counteracted the effect of reward salience, making it necessary for the physical salience to potentiate the effect of reward.